1. Field of the Invention
The present invention relates to a clear ink composition, an ink cartridge, an ink set, a method for producing an inkjet record, and a record, and more particularly to a clear ink composition or the like that has excellent storage properties and can provide a record whose recorded images have excellent coloring properties and glossiness.
2. Description of the Related Art
Inkjet recording is a printing method in which droplets of an ink composition are sprayed and deposited on paper or another recording medium to perform recording. This method is characterized in that sharp images having high resolution can be rapidly printed using a relatively inexpensive device.
In conventional practice, numerous proposals have been made concerning the ink compositions designed for use in records made by this inkjet recording method.
The need for higher-quality recorded images has become more urgent in recent years, and various measures have therefore been implemented in order to further improve the coloring properties and glossiness of such recorded images.
Various measures have also been implemented in order to improve the storage properties of ink compositions.
An ink composition that has adequate storage properties and is also adequate in terms of the coloring properties and glossiness of recorded images has yet to be provided, however.
For example, adding polyethyleneimine to a water-base pigment ink has been proposed in Japanese Patent Application Laid-open Nos. H6-329964, H10-36726, H10-60352, and elsewhere, but this approach is still disadvantageous in that the recorded images have inadequate coloring properties and glossiness, and the ink composition has inadequate storage properties.
Thus, techniques in which additives are introduced into colorant-containing ink compositions to formulate the desired ink compositions are disadvantageous in that the coloring properties and glossiness of recorded images vary with variations in the amount in which the ink compositions are deposited on the recording medium, as well as with the type, amount, and other attributes of the colorants contained in the ink compositions, making it impossible to obtain excellent coloring properties or uniform glossiness.
Another drawback of the techniques for formulating such ink compositions is the inability to improve glossiness in low-duty portions and in non-print portions not covered by these ink compositions.
In addition, improving coloring properties and glossiness together with the storage properties (storage stability) of an ink composition is important for forming high-quality images.
Consequently, an object of the present invention is to provide a highly storable ink composition capable of providing a record whose recorded images have excellent coloring properties and glossiness, and also to provide an ink cartridge, an ink set, a method for producing an inkjet record, and a record.